We focus special attention to the relationship between the formation of ribosomes and the function of ribosomes in macromolecule synthesis. Our major objectives are centered to the following three directions of research: (a) Ribosomal function in protein synthesis -- involvement of ribosomes in translational control of gene expression. In vitro protein-synthesizing system is used to elucidate the translational control mechanism involved in the development of bacteriophage T4 and T7. (b) Ribosomal function in RNA synthesis -- involvement of ribosomes (or ribosomal protein) in the control of RNA synthesis. In vitro RNA-synthesizing system using purified RNA polymerase is used to elucidate the mechanism and specificity involved in the stimulation of RNA synthesis by purified ribosomal protein. (c) Control of ribosomal RNA synthesis. In conjunction with (b), genetic control of ribosomal RNA synthesis in E. coli will be studied in an in vitro RNA-synthesizing system which initiates ribosomal RNA synthesis.